1. Field of the Invention
The present invention relates to a multi-system air conditioner including a plurality of indoor units.
2. Description of the Related Art
Known in the art is a multi-system air conditioner which includes one outdoor unit and a plurality of indoor units and provides a heat pump type refrigerating apparatus among the units.
The multi-system air conditioner of this type can heat or cool a plurality of rooms in a house or a building at a time and is convenient in this sense.
In those buildings, however, some having a computer room, some having a perimeter zone and some having an interior zone, a cooling request comes from a given location or locations and, at the same time, a heating request comes from other locations.
In this case, it is not possible to operate the air-conditioner such that one of the heating and cooling requests is given a priority over the other.
There is a possibility that a better environment will be created at some location but that the workers in other locations will feel uncomfortable or apparatuses, such as computers, in still other locations will sometimes fail.
Such an unfavorable condition or conditions are liable to occur in the buildings or the common houses having a plurality of rooms, often in the intervening season between the spring and the autumn.
A new air-conditioner emerges as in Published Examined Japanese Patent Application 61-45145, which discloses the concept of operating at least one of several indoor units in a cooling operation mode and one or more remaining indoor units in a heating operation mode. Such a type of air conditioner can eliminate the aforementioned drawbacks.
In the aforementioned air-conditioner, an outdoor heat exchanger acts as an evaporator and the heat of absorption of the outdoor heat exchanger and that of the cooling operation-side indoor unit are utilized as the liberation of heat of the heating operation-side indoor unit or units.
During the operation of the air-conditioner, a decline in the outer air causes frost to gradually occur on the surface of the outdoor heat exchanger, thus lowering the heating power level upon the continuance of that condition.
The conventional way of solving the aforementioned problem is by reversing the direction in which a refrigerant of a cooling operation cycle is flowed, as required, and thawing the frost on the outdoor heat exchanger by a hot version of a refrigerant which has been delivered from the compressor.
Since, in this case, the flow of the refrigerant is reversed in its direction, the liberation of heat on the heating operation-side indoor unit is interrupted, failing to create a comfortable atmosphere around the workers or occupants in the room.